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Similarity

Tools for set similarities.

jaccard

jaccard(a, b) computes the Jaccard similarity between two sets a and b.

jaccard(
    {1, 2, 3   },
    {1,    3, 5}
)
# 0.5 = 2 / 4

multisetjaccard

multisetjaccard(a, b) computes the Jaccard similarity between two multi-sets (Counters) a and b.

multisetjaccard(
    Counter([1, 1, 2, 3   ]),
    Counter([1,       3, 5])
)
# 0.4 = 2 / 5

weightedjaccard

weightedjaccard(a, b, key=sum) computes the weighted Jaccard similarity between two sets a and b, using function key to compute the total weight of the elements within a set.

weightedjaccard(
    {1, 2, 3   },
    {1,    3, 5}
)
# 0.36363636363636365 = (1 + 3) / (1 + 2 + 3 + 5) = 4 / 11

weightedjaccardjaccard(
    {1, 2, 3   },
    {1,    3, 5},
    key=len
)
# 0.5 = 2 / 4

weightedjaccard(
    Counter([1, 1, 2, 3   ]),
    Counter([1,       3, 5]),
    key=lambda c: sum(c.values())
)
# 0.4 = 2 / 5